Pyridoxal phosphate, tryptophan, and tyrosine in blood and cerebrospinal fluid in elderly patients.

In a material of 74 elderly patients with cerebral symptoms, most of them on account of atherosclerosis, deficiency of pyridoxal phosphate is uncommon: only ten had extremely low plasma levels. Nine of the patients had rather high levels of serum tryptophan. This might depend upon poor metabolization when pyridoxal phosphate is available in insufficient supply. In addition mean values are given for tryptophan, tyrosin and serotonin in this group of patients.